Re: code review for JVM/TI DynamicCodeGenerated event fix (7039447)

[Karen Kinnear]

Sorry, I didn't know you were going to redo this. I too have memories
of os::free of null having issues. And I also have memories of code checking
tools complaining about calls to os::free of null.

So, if you could either go back to the way it was, or only call
os::free if it is not null I would be much more comfortable.

thanks,
Karen

On 04/28/11 09:52, Daniel D. Daugherty wrote:

On 4/28/2011 7:37 AM, Daniel D. Daugherty wrote:

I'm going to take another look at what I can do to clean this
up a bit...

This version should address your concerns and Dmitry's also.
Especially since Dmitry suggested the specific code in the
post_dynamic_code_generated_internal() call. I just added
the comment and reformatted it a bit...

Dan


--- a/src/share/vm/prims/jvmtiImpl.cpp  Sat Apr 23 00:33:38 2011 -0400
+++ b/src/share/vm/prims/jvmtiImpl.cpp  Thu Apr 28 07:44:01 2011 -0600
@@ -38,6 +38,7 @@
#include "runtime/handles.inline.hpp"
#include "runtime/interfaceSupport.hpp"
#include "runtime/javaCalls.hpp"
+#include "runtime/os.hpp"
#include "runtime/serviceThread.hpp"
#include "runtime/signature.hpp"
#include "runtime/vframe.hpp"
@@ -939,10 +940,15 @@
  nmethodLocker::lock_nmethod(nm, true /* zombie_ok */);
  return event;
}
+
JvmtiDeferredEvent JvmtiDeferredEvent::dynamic_code_generated_event(
      const char* name, const void* code_begin, const void* code_end) {

JvmtiDeferredEvent event = JvmtiDeferredEvent(TYPE_DYNAMIC_CODE_GENERATED);

-  event._event_data.dynamic_code_generated.name = name;
+  // Need to make a copy of the name since we don't know how long
+  // the event poster will keep it around after we enqueue the
+  // deferred event and return. strdup() failure is handled in
+  // the post() routine below.
+  event._event_data.dynamic_code_generated.name = os::strdup(name);
  event._event_data.dynamic_code_generated.code_begin = code_begin;
  event._event_data.dynamic_code_generated.code_end = code_end;
  return event;
@@ -968,12 +974,17 @@
      nmethodLocker::unlock_nmethod(nm);
      break;
    }
-    case TYPE_DYNAMIC_CODE_GENERATED:
+    case TYPE_DYNAMIC_CODE_GENERATED: {
      JvmtiExport::post_dynamic_code_generated_internal(
-        _event_data.dynamic_code_generated.name,
+        // if strdup failed give the event a default name
+        (_event_data.dynamic_code_generated.name == NULL)
+          ? "unknown_code" : _event_data.dynamic_code_generated.name,
        _event_data.dynamic_code_generated.code_begin,
        _event_data.dynamic_code_generated.code_end);
+      // release our copy
+      os::free(_event_data.dynamic_code_generated.name);
      break;
+    }
    default:
      ShouldNotReachHere();
  }